I'm looking for details and experiences with rope-control skegs.

Bjorn Thomasson has details on his website.
http://www.thomassondesign.com/images/skeg-system.pdf

My questions are mostly about the on-deck control for the skeg:
Location and thru-deck fitting
Arrangement of line and shock cord or other 'locking' device
Marking to indicate degree of up/down skeg
Usability with one hand

Any pictures or comments? Thanks!